Got out to the shop for a bit. Just a little project to add a very small dog door to a security screen door. The HOA limits what designs can be used, so I tried to make this blend in as much as practical.
Cut out a section of screen and made a small frame for it by slitting some 3/16" steel brake line with a small cut-off wheel then notching it to fold around the piece of removed screen. I also used a small piece, to cover the upper edge of the hole. Squeezed the tubing to close up the slit and clamp on to the screen. TIG brazed the cuts in the corners, and the upper tube on. 8 amps did the job with silicone bronze. Used some aluminum strip to cover the cut edges on the sides, held on with a few rivets.

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Painted everything up and installed a couple of stainless screws to act as hinge pins in the upper tube.

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Came out pretty good. From a distance you can barely tell that is has been modified.